Here is the scenario. This is happening with what we have in
wireless-testing code
When hw queue get full we call
ieeee80211_stop_queue(dev, q);
When this is happens in the middle of the fragmentation . This is
easiest to reproduces with fragmentation but probably happens also in
other cases.
int __ieee80211_tx()
....
if (netif_subqueue_stopped(local->mdev,
tx->extra_frag[i]))
return IEEE80211_TX_FRAG_AGAIN;
The fragment should stored into local->queues_pending[queue]
(Actually I'm not sure it is)
now when we HW queue got cleared a bit we call wake queues where
tx_pending_tasklet is woken up ( queue is not woken up here)
void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
{
struct ieee80211_local *local = hw_to_local(hw);
if (test_bit(queue, local->queues_pending)) {
tasklet_schedule(&local->tx_pending_tasklet);
}
..... <snip>
}
The check if the queue is open causes that queue is actually never
woken up so traffic is stalled. However removing this line causes some
other panic I didn't have time to process.
void ieee80211_tx_pending(unsigned long data)
{
<snip>
netif_tx_lock_bh(dev);
for (i = 0; i < ieee80211_num_regular_queues(&local->hw); i++) {
/* Check that this queue is ok */
if (__netif_subqueue_stopped(local->mdev, i))
--- This line causes that fact that the actual wake queue is never
called.
continue;
if (!test_bit(i, local->queues_pending)) {
ieee80211_wake_queue(&local->hw, i);
continue;
}
</snip>
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